Merbau Product Information

What makes Merbau decking different from other decking timbers?
Merbau is a class 1 durable species, meaning it has the highest above-ground durability rating available. With proper installation, including adequate gapping and ventilation, Merbau can last over 40 years. Stability is another key advantage, as Merbau has low dimensional movement, reducing the risk of splitting, cupping, or twisting compared to other decking timbers.

What makes Merbau decking different from other decking timbers?
Merbau timber is a natural, renewable resource sourced from FSC-certified forests, offering sustainability and wellbeing benefits through biophilic design. It can be repurposed or decomposed naturally at the end of its life. Plastic composite decking, on the other hand, cannot be recycled once it reaches the end of its lifespan and is prone to higher temperatures under the sun, static electricity, and replacement if scratched.

How long does Merbau decking last?
Merbau decking has a class 1 durability rating, meaning it can last over 40 years when installed and maintained correctly. It is naturally resistant to termites and less prone to rot and decay compared to other decking timbers.

Does Merbau decking have a slip rating?
In its pre-oiled condition, SpecRite Merbau decking does not have a slip resistance rating. If slip resistance is required, such as for poolside areas, a specialised slip-resistant finish like Intergrain UltraDeck Slip should be applied.

Does Merbau timber bleed?
Yes, Merbau contains high tannin levels, which can leach when first exposed to moisture. This can cause staining on nearby surfaces. To reduce tannin bleeding, a thorough and regular hose-down during the initial days of installation can help. Products like Intergrain Ultraprep Tannin and Oil Remover can also accelerate the process.

Can Merbau be used in bushfire-prone areas?
Yes, Merbau is rated BAL 29, meaning it is suitable for use in bushfire-prone areas rated at Bushfire Attack Level (BAL) 29 or lower. However, it is important to check local building regulations for specific installation requirements.

Is SpecRite Merbau decking termite resistant?
Yes, Merbau timber is naturally resistant to termites, fungi, and dry wood borers, eliminating the need for chemical treatments.

Is Merbau a sustainable timber choice?
Historically, Merbau has been linked to deforestation and illegal logging, but SpecRite sources its Merbau from FSC 100% certified forests. The FSC certification ensures responsible forest management that supports biodiversity, climate resilience, workers’ rights, and sustainable practices.

Merbau Installation

Should I use screws or nails for Merbau decking installation?
Merbau decking should be fixed using hot-dipped galvanised or stainless steel screws, with two screws per joist. Pre-drilling and countersinking are recommended to prevent splitting and achieve the best finish. Stainless steel fixings are ideal for coastal or poolside applications.

Do I need to leave gaps between decking boards?
Yes, proper gapping and ventilation are essential for the longevity of your deck. Without sufficient ventilation, moisture can accumulate, leading to cupping, twisting, and splitting. Although Merbau is highly stable, poor installation can still lead to performance issues.

Does ‘pre-oiled’ mean I don’t need to oil my deck?
No, SpecRite’s Pre-Oiled Merbau Decking has been primed with Feast Watson® Industrial Timber Oil, but it still requires top coating with either a water-based or oil-based finish for long-term protection.

Merbau Care & Maintenance

How often should I oil my Merbau deck?
To maintain the natural beauty of your Merbau deck, regular deck oiling is required. The frequency depends on factors such as exposure to the elements and the oil product used. Fully exposed decks may require re-coating every 12 months, while partially covered decks may last up to 3 years. For those who prefer a natural greying look, maintenance is not necessary.

What oil should I use on my Merbau deck?
SpecRite Merbau is pre-oiled with Feast Watson® Industrial Timber Oil, which is compatible with most water-based and oil-based topcoats. For maintaining a natural appearance, a lightly pigmented oil like Feast Watson® Traditional Timber Oil is recommended. For long-lasting protection, Intergrain® UltraDeck Timber Oil is a great choice. If a deeper colour transformation is desired, Intergrain® UltraDeck Timber Stain can be used.

Can GL17 Merbau posts be used in-ground?
No, SpecRite GL17 posts are designed for above-ground use only. While Merbau has a class 1 durability rating above ground, its durability is class 3 when used in-ground, meaning it will last only 7-15 years. Additionally, ground contact can cause excessive swelling, which may weaken glue joints.

Troubleshooting

How can I remove tannin stains from my Merbau deck?
A diluted oxalic acid solution can be used to reduce tannin stains. Always follow safety guidelines when using chemical treatments. Over time, exposure to sunlight will also help fade tannin stains naturally

What causes black marks on my Merbau decking?
Black blotches are often caused by iron stain, which occurs when metal comes into contact with tannins in the timber. Common sources include water run-off from iron roofs, metal objects left on the deck, construction debris, fertilisers, or trace iron in water. Iron stains do not damage the timber and can be removed with oxalic acid, scrubbing, or sanding. Identifying and eliminating the contamination source will prevent recurrence.

Edge of deck with step with garden lawn in background

Resources

Decking Calculator

How-To Articles

Why Merbau

FAQs